There is a continuing need for methods and products which increase weight gain and feed utilization efficiency in animals. For animals fed diets containing grain, these goals can be achieved by increasing the availability to the animal of the starch, protein and other nutrients found in the grain. The availability of these nutrients can be increased by breaking open the outer coating of the grain and by enlarging the surface area of the grain so that the enzymes and bacteria in the digestive tract of the animal can more easily penetrate the grain and can have access to more of the grain. Weight gain and feed utilization efficiency can be further improved by increasing the moisture content of the grain which also makes it easier for the enzymes and bacteria in the digestive tract to penetrate the grain. Also, the digestive enzymes cannot work until a certain level of moisture in the grain is achieved.
Several techniques are known for processing grains which serve these purposes. For instance, grain can be ground or rolled thereby breaking open the outer coating of the grain and enlarging its surface area. The grain can be soaked or sprayed with water before or after the rolling or grinding to increase its moisture content. To further increase the moisture content, grain conditioners can be added to the water. Grain conditioners are preparations that increase penetration of moisture into the grain. They contain either surfactants, acids or bases. Instead of soaking or spraying the grain with water, early-harvested grain that naturally has a higher moisture content may be used. Other methods of processing grain-include steam rolling, steam flaking, popping, exploding and mechanically scarifying.
The mechanical scarification of grains is described in U.S. Pat. Nos. 3,962,479 and 3,861,294. The method described in these patents comprises wetting the exterior of the kernels of grain so that the husks separate partially from the interior portion of the grain in the form of blisters. Next, the blisters are perforated. After perforation of the blisters, the grain may be wetted with water. Feed supplements which are soluble in water may be mixed with the water used to wet the grain. The patents teach that the absorption of water by the grain activates the naturally-occurring enzymes in the grain and that these enzymes co-act with the water to convert or liquify the starch which, in turn, allows the animals to assimilate a greater quantity of the nutrients contained in the grain.
The addition of enzymes to animal feeds is also known to increase feed utilization efficiency and weight gain. For instance, U.S. Pat. No. 2,906,621 (Catron) describes the use of a combination of amylolytic and proteolytic enzymes as an additive in animal feeds. In particular, Catron teaches the use of enzyme mixtures having both proteolytic and amylolytic activities which are obtained from various strains of Aspergillus, Rhizopus and Bacillus. Catron also teaches that lipolytic and cellulolytic enzymes may be added to the animal feeds along with the amylolytic and proteolytic enzymes. However, Catron teaches the use of these enzyme only for baby animals whose enzyme systems are incomplete.
U.S. Pat. No. 3,151,983 (Ely et al.) teaches that a feed supplement comprising a mixture of a material prepared by fermenting wet wheat bran using Aspergillus orizae and a material prepared by fermenting wet wheat bran using Bacillus subtilis results in both increased efficiency of feed utilization and weight gain in animals fed feeds containing barley which are supplemented with these materials. The increase in efficiency of feed utilization is disclosed to be due to the presence of the proteolytic and amylolytic enzymes in the two fermented materials, but the increase in growth response is believed to be due to an unknown, nonenzymatic growth factor.
U.S. Pat. No. 3,880,742 (James et al.) discloses the incorporation of a thermostable beta-glucanase into animal feeds containing barley to degrade the barley beta-glucan. James et al. teaches that the beta-glucanase can be added as a fermentation extract of Penicillum emersonii and that the fermentation extract also typically contains cellulase and alpha-amylase. The patent teaches that liquid beta-glucanase-containing fermentation extract may be sprayed onto animal feed pellets containing barley or that the enzyme in dry form or which has been absorbed onto an absorbent solid (such as ground wheat or barley) and dried can be incorporated into the feed mix containing barley before it is pelleted. Finally, James et al. teaches that the use of the beta-glucanase in animal feeds containing barley increases the nutritional value of the feed by promoting degradation of the beta-glucan content of barley and causes increased weight gain.
U.S. Pat. No. 4,259,358 (Duthie) teaches treating a slurry of legumes under controlled conditions of time, temperature and pH with a variety of enzymes. The resultant enzyme-digested product can be fed to young animals and certain older animals such as hogs, horses, cats, dogs and humans. Duthie discloses that amylase and amyloglucosidase can be used to digest the starch in the legumes and that proteases, cellulases, hemicellulases and pectinases may be employed to digest, respectively, protein, cellulose, hemicellulose and pectin. The Duthie patent does not teach, and specifically disclaims, the use of enzymes on cereal grains such as wheat, oats, barley and milo.
U.S. Pat. Nos. 2,988,448 (the '448 patent) and 2,988,449 disclose that using diastatic barley malt as an enzyme supplement for animals feeds containing barley and other fibrous grains results in increased weight gain and feeding efficiency. Both of the patents attribute the increases to the cytolytic enzymes (cytases, gumases (beta-glucanases) and beta-polyglucosidases) present in the barley malt. Further, the '448 patent teaches that a combination of diastatic barley malt and fungal enzyme preparations act synergistically in increasing the value of barley and other fibrous grains in animal feeds. The mechanism of the action of the enzyme preparations is believed to be due to the action of cytases in these preparations which degrade the non-starch carbohydrate material commonly referred to as gums (beta-glucan).
U.S. Pat. No. 4,208,433 (Barham et al.) discloses a method for the absorption of solids by the tissues of whole grain seeds comprising contacting the whole grain seed with a mixture of a solid material (such as an enzyme) and an oleaginous vehicle (such as vegetable oil) and maintaining contact until the mixture has been absorbed by the grain. Barham et al. disclose that the absorption of proteolytic enzymes into the seed endosperm in this manner causes the degradation of the protein matrix under appropriate superimposed moisture and temperature conditions and that the degradation of the starch-protein matrix enhances the general availability of starch and protein to the animal. The patent also discloses that the absorption of amylolytic enzymes would cause the partial digestion of the starch which would be advantageous to the animal.
Numerous patents disclose the use of proteolytic enzymes as supplements in animal feeds. These include U.S. Pat. Nos. 2,450,318, 2,878,123, 3,674,644, 4,062,732, 4,073,884, 4,235,878, 4,235,879, 4,235,880, 4,239,750, 4,218,437 and 4,225,584.
Several patents disclose the use of micro-organisms or ferments of microorganisms (containing or capable of producing enzymes) as feed supplements. These are U.S. Pat. Nos. 1,615,024, 1,685,004, 2,450,318, 2,452,534, 2,700,611, 3,455,696, 4,035,516 and 4,582,708.